docs: def setup_rabbitmq(self):
          """ Setup RabbitMQ connection.
  
              Call this method after spider has set its crawler object.
          :return: None
          """
  
          if not self.rabbitmq_key:
              self.rabbitmq_key = '{}:start_urls'.format(self.name)
  
          self.server = connection.from_settings(self.crawler.settings)
          self.crawler.signals.connect(self.spider_idle, signal=signals.spider_idle)
          self.crawler.signals.connect(self.item_scraped, signal=signals.item_scraped)